If you have lived your life in manufacturing, you know that really in comparison to other industries, not much changes. So when there is a product that offers improvements to a process, it is pretty exciting. For years most hydraulic manifold manufacturers struggled when designing a part because the tolerances offered in Aluminum extruded bar were so liberal. How can someone expect me to work with +/-.024” on a 3” square? I want to design around a 3” nominal dimension, but if it can run .024” under that I have to start 3.250” and machine it down. These are just some of the dilemmas of the past in designing manifolds for the hydraulics industry. What if someone were to improve the tolerances and put them all on the plus side? Fortunately the large hydraulics companies put pressure on the large Aluminum extrusion producers and they stepped up with a product called Manifold Quality Bar. Manifold quality aluminum bar is an extruded product with improved dimensional tolerances and characteristics that make it a preferred choice for a multitude of applications including hydraulic cylinder producers. First and most notably, all the “manifold quality bar stock” supplied bar Howard Precision Metals is extruded to half commercial AA tolerances, all on the plus side. This means that no material is produced undersized and the tolerances on manifold bar are half that of standard aluminum extruded bar stock. Available in rectangles and squares, manifold quality bar stock is also produced with improved twist, flatness, and straightness tolerances, which lend to better machinability. It is because of these improvements that manifold quality bar is able to withstand very complex machining, including removal of large voids. At Howard Precision Metals, we stock an expansive inventory of aluminum extrusions, in both manifold and standard commercial quality. We are sure to have the size you need for your next aluminum extrusion requirement.
Not all bar is produced to Manifold Quality Standards
Don’t assume that if you are buying Aluminum Bar it will meet Manifold tolerances and machinability. It takes a special extrusion process and oversight at the mill to meet the standards of Manifold Quality. The term Manifold Quality is a generic reference to the improvement on Aluminum Association Tolerances, but that does not mean you are getting the controlled chemistry that provides the improved machinability and consistency. Some of the major players have trade marked their product with it’s own name. For instance. Hydro Aluminum formerly Sapa, calls their product Acc-u-bar +, and Service Center Metals calls their product Thunderbar, while Kaiser Aluminum calls their product Kaiser Select Manifold Bar. For all intents and purposes each of these major extrusion players have refined their processes to produce the tolerances and machinability promised. It is important to note that each of these extrusions producers has the ability to cast their own billet in house, so they are able to guarantee the refined chemistry giving the improvements to the machinability. Do not be fooled by product produced at smaller or foreign extruders. Only the 3 listed above have defined the recipe and produce it in house to assure the consistency.
Manifold Bar Alloy and Temper
As a stand-alone element, aluminum is not very strong but alloying it together with other elements makes it nearly as strong as steel. Manifold bar is produced in an alloy and temper designation of 6061-T6511. With the addition of silicone, magnesium and other elements to aluminum, the result is the 6061 alloy. Properties such as a high strength-to-weight ratio, nice surface finish, and machinability make alloy 6061 an economical choice for a variety of applications and products, including extruded aluminum bar. The temper, -T6511, adds heat treatment and artificial aging for additional strength and stretching for stress relief. With the tolerances and the characteristics of 6061-T6511, it is the optimal choice for manifold bar production, but Manifold Quality Bar is not your standard 6061 T6511 chemistry. A refinement of the recipe has been created to not only improve the machinability but also to offer a guaranteed increased strength. Where typically 6061 T6511 has a tensile of 38,000ksi tensile and 35,000ksi yield, manifold quality offers 42,000ksi Tensile and 38,000ksi Yield.
What is Unique About Manifold Quality Bar?
In addition to being produced to half-commercial, plus side only tolerances, manifold bar is known for its ability to undergo complex machining processes successfully with high metal removal rates. When compared against other bar products, it offers enhanced and repeatable performance – piece-to-piece and lot-to-lot. Additional improvements of manifold bar include dimensional control, flatness, and straightness.
Properties of Manifold Bar
Manifold bar offers significant hardness and enhanced mechanical strength. Smaller chip sizes and reduced burr formation contribute to its high machining performance. Machining throughput is improved due to the compact chips that are a result of boring and drilling. This enables consistency during the mechanical process.
Available Sizes
Manifold bar is available in rectangles and squares, with manifold quality rectangles produced in sizes from 1.00″ x 1.25″ and available up through 6.00″ x 8.00″, and manifold quality squares produced in sizes from .875″ and available as large as 7″. Our premier mill sources also have the ability to produce custom rectangle and square sizes to manifold quality specifications. For more information on manifold bar or aluminum products call Howard Precision Metals today at 800.444.0311 or request a quote on our website.
